Misalignment detection devices

ABSTRACT

A misalignment detection device comprising a first substrate, at least one integrated circuit, a second substrate, a third substrate, and at least one detection unit. The at least one integrated is disposed on the first substrate in a first pressing region. The third substrate is disposed on the first substrate in a second pressing region and on the second substrate on the second substrate in a third pressing region. The at least one detection unit outputs a fault signal in response to a positioning shift occurring in at least one of the first, second, and third pressing regions.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a division of U.S. patent application Ser. No. 12/700,871, filed Feb. 5, 2010 and entitled “Misalignment Detection Devices,”, which is a division of U.S. patent application Ser. No. 11/535,141, filed Sep. 26, 2006 (now U.S. Pat. No. 7,683,496) and entitled “Misalignment Detection Devices,” which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a misalignment detection device, and more particularly, to a misalignment detection device applied in pressure exerted on an integrated circuit and at least one substrates.

2. Description of the Related Art

In nowadays electronic devices, elements are connected to a major circuit through conductive films, such as anisotropic conductive films (ACFs), which are formed by mixing non-conductive resins and conductive particles. FIG. 1A is a cross-sectional view of a conductive particle 1. The diameter of the conductive particle 1 is about 3 μm to about 5 μm. The center portion 1 a of the conductive particle 1 is formed by a polymer, and the conductive particle 1 is covered externally by a metal conductor 1 b, such as gold, silver, nickel, tin, copper, or the like.

ACFs are typically used for the manufacture of displays. In a manufacturing method, an ACF is used to directly dispose the driving chips of a panel on a glass substrate, known as the Chip-On-Glass (COG) procedure or an ACF is used to dispose the driving chips on a flexible printed circuit (FPC), known as the Chip-On-Film (COF) afterward the FPC is electrically coupled to a substrate. In addition, an ACF is used to dispose the driving chips on a printed circuit board (PCB), known as the Chip-On-Board (COB).

FIG. 1B shows pressure between a substrate and a driving chip through an ACF. Referring to FIG. 1B, a substrate 10 can be a glass substrate, an FPC, a PCB, or other circuit boards. During manufacture, metal pads 10 a are formed on the substrate 10 to transmit signals or power, such as voltage level, current, or likes. Thick bumps 11 a are formed on pins of the driving chip 11. An ACF 12 is then disposed between the driving chip 11 and the substrate 10. ACF 12 is heated to increase adhesion capability, and then applying a pressure on the driving chip 11 and the substrate 10 so as to assembly. Note that the pads 10 a and the corresponding bumps 11 a must be aligned.

Since each bump 11 a has a fixed thickness, conductive particles 1 are compressed between the pads 10 a and the bumps 11 a. Through metal conductors 1 b externally covering the conductive particles 1, the compressed conductive particles 1 electrically connected to the bumps 11 a and the pads 10 a. Thus, the motion of the driving chip 11 and the coupling of circuits are performed at the same time by ACFs.

During manufacture, the accuracy of disposition alignment is determined by the naked eye of the operator, thus, a great number of detection operators is required. Moreover, the accuracy of disposition alignment may be suffered due to erroneous detection by operators or an insufficient sampling rate.

As shown in FIG. 2A, the misalignment occurs between the bump 11 a of the driving chip 11 and the pad 10 a of the substrate 10. The bump 11 a is electrically connected to a pad adjacent to the corresponding pad 10 a, and the misalignment thus occurs. In another case as shown in FIG. 2B, although the bump 11 a is not electrically connected to the next pad, a short path is formed between the bump 11 a and the pad adjacent to the corresponding pad 10 a via the conductive particle 1. If erroneous or incomplete detection occurred by the operators leading to produce the defective products.

BRIEF SUMMARY OF THE INVENTION

Misalignment detection devices are provided. An exemplary embodiment of a misalignment detection device comprises a first substrate, at least one integrated circuit, a second substrate, a third substrate, and at least one detection unit. The first substrate comprises a first positioning pad, a second positioning pad adjacent to the first positioning pad, a first positioning electrode, and a second positioning electrode adjacent to the first positioning electrode. The at least one integrated circuit with a first pressing region is disposed on the first substrate and comprises a first positioning bump and a second positioning bump adjacent to the first positioning bump. The first positioning bump and the second positioning bump substantially correspond to the first positioning pad and the second positioning pad in the first pressing region, respectively. The second substrate comprises a third positioning electrode and a fourth positioning electrode adjacent to the third positioning electrode. The third substrate with a second pressing region and a third pressing region is electrically coupled between the first and second substrates and comprises a fifth positioning electrode, a sixth positioning electrode adjacent to the fifth positioning electrode, a seventh positioning electrode, and a eighth positioning electrode adjacent to the seventh positioning electrode. The fifth positioning electrode and the sixth positioning electrode substantially correspond to the first positioning electrode and the second positioning electrode in the second pressing region, respectively, and the seventh positioning electrode and the eighth positioning electrode substantially correspond to the third positioning electrode and the fourth positioning electrode in the third pressing region, respectively. The at least one detection unit is electrically coupled to the second substrate. The at least one detection unit outputs a fault signal in response to a positioning shift occurring in at least one of the first, second, and third pressing regions.

A detailed description is given in the following embodiments with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings, given by way of illustration only and thus not intended to be limitative of the present invention.

FIG. 1A is a cross-sectional view of a conductive particle of an ACF;

FIG. 1B shows pressure between a substrate and a driving chip through an ACF;

FIG. 2A shows misalignment occurring between a driving chip and a substrate;

FIG. 2B shows a short path formed by conductive particles of an ACF;

FIG. 3A shows a first embodiment of a misalignment detection device of the present invention;

FIG. 3B shows misalignment occurring in the embodiment of the misalignment detection device of FIG. 3A.

FIG. 4 shows a short path formed by conductive particles of an ACF in an embodiment of a misalignment detection device;

FIG. 5 shows distances between positioning pads between function pads in an embodiment of a misalignment detection device of the present invention;

FIG. 6A shows a second embodiment of a misalignment detection device of the invention;

FIG. 6B is a cross-sectional view of the exemplary embodiment of the misalignment detection device in FIG. 6A;

FIG. 7 shows a third embodiment of a misalignment detection device of the present invention;

FIG. 8 shows distances between positioning pads between function pads of a first substrate in FIG. 7;

FIG. 9 shows distances between positioning electrodes between function electrodes of a first substrate in FIG. 7; and

FIG. 10 shows distances between positioning electrodes between function electrodes of a second substrate in FIG. 7.

DETAILED DESCRIPTION OF THE INVENTION

The following description is of the preferred embodiments of carrying out the present invention. This description is made for the purpose of illustrating the general principles of the present invention and should not be taken in a limiting sense. The scope of the present invention is best determined by reference to the appended claims.

Misalignment detection devices are provided. In a first embodiment of a misalignment detection device in FIG. 3A of the present invention, a misalignment detection device 3 comprises a substrate 30, at least one integrated circuit (IC) 31, and at least one detection unit 32. In present embodiment of the invention, the substrate 30 can be a transparent substrate (such as a glass substrate, or a quartz substrate), an opaque substrate (such as a wafer or ceramic substrate), or flexibility substrate (such as acrylic polymer, rubber, epoxy polymer, ester polymer, or likes). In the following description of FIG. 3A, a glass substrate is given as an example for the substrate 30, but non-limited it. Referring to FIG. 3A, the substrate 30 comprises a plurality of pads divided into function pads 30 c and two adjacent positioning pads 30 a and 30 b. The distance between any two of the function pads 30 c is substantially greater than the distance between of the positioning pads 30 a and 30 b. The IC 31 comprises a plurality of bumps divided into function bumps 31 c and two adjacent positioning bumps 31 a and 31 b. An ACF 33 is disposed between the substrate 30 and the IC 31. The ACF 33 is heated to increase adhesion capability, and then applying a pressure on the substrate 30 and the IC 31. Preferably, the function pads 30 c and the substantially corresponding function bumps 31 c should be aligned, and the positioning pads 30 a and 30 b and the substantially corresponding position bumps 31 a and 31 b should be aligned.

In the present embodiment of the invention, the positioning pads 30 a and 30 b receive signals S30 a and S30 b having substantially different voltage levels, respectively. When the misalignment detection device 3 is applied in a display device, at least one of the signals S30 a and S30 b is disregards display device functions. In other words, at least one of the signals S30 a and S30 b is not provided by the display device. For example, the signal S30 a has the same level as a common voltage Vcom of the display device, and the signal S30 b has a ground level GND provided by the misalignment detection device 3 or an external device (not shown).

The detection unit 32 is electrically coupled to the substrate 30 and detects the signals S30 a and S30 b. As shown in FIG. 3B, when the positioning shift occurs between the substrate 30 and the IC 31, the detection unit 32 outputs a fault signal S32. In detail, when the positioning shift occurs between the substrate 30 and the IC 31 and the misalignment is caused between the function pads 30 c and the function bumps 31 c, the positioning pad 30 a is electrically coupled to the positioning bump 31 b or the positioning pad 30 b is electrically coupled to the positioning bump 31 a, at the same time, one function pad 30 c is electrically coupled to a function bump adjacent to the substantially corresponding function bump 31 c. One of the signals S30 a and S30 b is not at the original voltage level. When detecting that the voltage level of one of the signals S30 a and S30 b is changed, the detection unit 32 outputs the fault signal S32 to indicate a positioning shift between the substrate 30 and the IC 31. The display device displays images incorrectly according to the fault signal S32, and the disposition of the substrate 30 and the IC 31 faults.

In the present embodiment of the invention, the distance between two function pads 30 c is substantially greater than the distance between the positioning pads 30 a and 30 b. When the positioning shift occurs between the substrate 30 and the IC31, the positioning pad 30 a has been electrically coupled to the positioning bump 31 b or the positioning pad 30 b has been electrically coupled to the positioning bump 31 a, notwithstanding any one of the function pads 30 c may not yet be electrically coupled to a function bump adjacent to the substantially corresponding function bump 31 c causing the misalignment. Thus, the positioning shift between the substrate 30 and the IC 31 can be determined in advance, decreasing the probability of the misalignment.

In FIG. 3A, the distance between two function pads 30 c is substantially greater than the distance between the positioning pads 30 a and 30 b. In some cases, although the positioning shift does not occur between the substrate 30 and the IC 31, the conductive particles of the ACF 33 form a short path between the positioning bumps and the positioning pads due to the shorter distance between the positioning pads 30 a and 30 b, as shown in FIG. 4. In order to prevent the short path formed by the conductive particles of the ACF 33, the forms of the positioning pads 30 a and 30 b can be made as shown in FIG. 5. In FIG. 5, the positioning pad 30 a comprising two portions 50 a and 50 b, and the positioning pad 31 a comprising two portions 51 a and 51 b. The distance between the positioning pads 30 a and 30 b has the maximum length Lmax and the minimum length Lmin. It is assumed that the distance between two function pads 30 c is about 20 um, the maximum length Lmax is substantially equal to 20 um, and the minimum length Lmin is substantially less than 20 um. Thus, when the positioning shift occurs between the substrate 30 and the IC 31 and the misalignment has not yet been caused between the function pads 30 c and the function bumps 31 c, the positioning pad 30 a has been electrically coupled to the positioning bump 31 b or the positioning pad 30 b is coupled to the positioning bump 31 a, thereby the positioning shift between the substrate 30 and the IC 31 can be known in advance. Moreover, because the distance between the portions 50 b and 51 b of the positioning pads 30 a and 30 b is less than about 20 um, the short path formed by the conductive particles of the ACF 33 can be prevented.

In the present embodiments of the invention, the positioning bumps 31 a and 31 b are disposed on an outer side of the IC 31, in other words, the positioning bumps 31 a and 31 b are disposed on one of the two sides of the function bumps 31 c.

In a second embodiment of a misalignment detection device in FIG. 6A of the present invention, a misalignment detection device 6 comprises a first substrate 60, a second substrate 61, and at least one detection unit 62. The second substrate 61 is electrically coupled to and disposed on partly of the first substrate 60. The first substrate 60 can be a printed circuit board (PCB), a flexible printed circuit (FPC), COF, or a combination thereof. The second substrate 61 can be a PCB, an FPC, or a combination thereof. In present embodiment of the invention, the first substrate 60 is a PCB, and the second substrate 61 is an FPC is given as an example, but non-limited it. Referring to FIG. 6A, the first substrate 60 comprises a plurality of electrodes divided into function electrodes 60 c and two adjacent positioning electrodes 60 a and 60 b, and the second substrate 61 comprises a plurality of electrodes divided into function electrodes 61 c and two adjacent positioning electrodes 61 a and 61 b. Referring to FIG. 6 b, an ACF 63 is disposed between the first substrate 60 and the second substrate 61. The ACF 63 is heated to increase adhesion capability, and then applying a pressure on the first substrate 60 and the second substrate 61. Preferably, the function electrodes 60 c of the first substrate 60 and the function electrodes 61 c of the first substrate 60 should be aligned, and the positioning electrodes 60 a and 60 b of the first substrate 60 and the positioning electrodes 61 a and 61 b of the first substrate 60 should be aligned.

In the present embodiment of the invention, at least one of the distance between two of the function electrodes 60 c of the first substrate 60 is substantially greater than the distance between the positioning electrodes 60 a and 60 b or the distance between two function electrodes 61 c of the second substrate 61 is substantially greater than the distance between the positioning electrodes 61 a and 61 b. In the following description, the distance between two function electrodes 60 c of the first substrate 60 is substantially greater than the distance between the positioning electrodes 60 a and 60 c.

The positioning electrodes 60 a and 60 b respectively receives signals S60 a and S60 b which have substantially different voltage levels. When the misalignment detection device 6 is applied in a display device. At least one of the signals S60 a and S60 b disregards display device function. In other words, at least one of the signals S60 a and S60 b is not provided by the display device. For example, the signal S60 a has the same level as a common voltage Vcom of the display device, and the signal S60 b has a ground level GND provided by the misalignment detection device 6 or an external device (not shown).

The detection unit 62 is electrically coupled to or disposed on the first substrate 60. The detection unit 62 detects the signals S60 a and S60 b. When a positioning shift occurs between the first substrate 60 and the second substrate 61, the detection unit 62 outputs a fault signal S62. In detail, when the positioning shift occurs and the misalignment is thus caused between the function electrodes 60 c and the function electrodes 61 c, the positioning electrode 60 a is electrically coupled to the positioning electrode 61 b or the positioning electrode 60 b is electrically coupled to the positioning electrode 61 a, at the same time, one function electrode 60 c of the first substrate 60 is electrically coupled to a function electrode adjacent to the substantially corresponding function electrode 61 c of the second substrate 61. One of the signals S60 a and S60 b is not at the original voltage level. When detecting that the voltage level of one of the signals S60 a and S60 b is changed, the detection unit 62 outputs the fault signal S62 to indicate the positioning shift occurs between the first substrate 60 and the second substrate 61.

In the present embodiment, the distance between two function electrodes 60 c of the first substrate 60 is substantially greater than the distance between the positioning electrodes 60 a and 60 b thereof. When the positioning shift occurs between the first substrate 60 and the second substrate 61, the positioning electrode 60 a has been electrically coupled to the positioning electrode 61 b or the positioning electrode 60 b has been electrically coupled to the positioning electrode 61 a although any one of the function electrodes 60 c of the first substrate 60 is not yet electrically coupled to a function electrode adjacent to the substantially corresponding function electrode 61 c of the second substrate 61 causing misalignment. Thus, the positioning shift between the first substrate 60 and the second substrate 61 can be known in advance, decreasing the probability of the misalignment.

In FIG. 6A, the distance between two function electrodes 60 c is substantially greater than the distance between the positioning electrodes 60 a and 60 b. In some cases, although the positioning shift does not occur between the first substrate 60 and the second substrate 61, the conductive particles of the ACF 63 form a short path between the positioning electrodes 60 a and 60 b and the positioning electrodes 61 a and 61 b due the shorter distance between the positioning electrodes 60 a and 60 b. In order to prevent the short path formed by the conductive particles of the ACF 63, the positioning electrodes 60 a and 60 b can be formed as shown in FIG. 5. The distance between the positioning electrodes 60 a and 60 b has the maximum length Lmax and the minimum length Lmin. It is assumed that the distance between two function electrodes 60 c is about 20 um, the maximum length Lmax is substantially equal to 20 um, and the minimum length Lmin is substantially less than 20 um. Thus, when the positioning shift occurs between the first substrate 60 and the second substrate 61 and the misalignment is not yet caused between the function electrodes 60 c and the function electrodes 61 c, the positioning electrode 60 a has been electrically coupled to the positioning electrode 61 b or the positioning electrode 60 b is electrically coupled to the positioning electrode 61 a, thereby the positioning shift between the first substrate 60 and the second substrate 61 can be known in advance. Moreover, because the distance between one portion of the positioning electrode 60 a and one portion of the positioning electrode 60 b is less than about 20 um, the short path formed by the conductive particles of the ACF 63 can be prevented.

In the present embodiment, the positioning electrodes 60 a and 60 b are disposed on an outer side of the first substrate 60, in other words, the positioning electrodes 60 a and 60 b are disposed on one of the two sides of the function electrodes 60 c.

In a third embodiment of a misalignment detection device in FIG. 7 of the present invention, a misalignment detection device 7 comprises an integrated circuit (IC) 70, a first substrate 71, a second substrate 72, a third substrate 73, and at least one detection unit 74. The third substrate 73 is electrically coupled to and disposed on the first substrate 71 and the second substrate 72. The first substrate 71 can be a transparent substrate (such as a glass substrate, or a quartz substrate), an opaque substrate (such as a wafer or porcelain substrate), or flexible substrate (such as acrylic polymer, rubber, epoxy polymer, or ester polymer). The second substrate 72 can be a printed circuit board (PCB), a flexible printed circuit (FPC), COF, or a combination thereof. The third substrate 73 can be a PCB, a FPC, a COF, or a combination thereof. In some embodiments, the first substrate 71 is a glass substrate, the second substrate 72 is a PCB, and the third substrate 73 is an FPC. Referring to FIG. 6A, the IC 70 comprises a plurality of bumps divided into function bumps 70 c and two adjacent positioning bumps 70 a and 70 b. The first substrate 71 comprises a plurality of pads divided into function pads 71 c and two adjacent positioning pads 71 a and 71 b, and the distance between any two of the function pads 71 c is substantially greater than the distance between the positioning pads 71 a and 71 b. The first substrate 71 further comprises a plurality of electrodes divided into function electrodes 71 f and two adjacent positioning electrodes 71 d and 71 e. The second substrate 72 comprises a plurality of electrodes divided into function electrodes 72 c and two adjacent positioning electrodes 72 a and 72 b. The third substrate 73 comprises a plurality of electrodes on two sides. On one side of the third substrate 73, the electrodes are divided into function electrodes 73 c and two adjacent positioning electrodes 73 a and 73 b; and on the other side thereof, the electrodes are divided into function electrodes 73 f and two adjacent positioning electrodes 73 d and 73 e. In FIG. 7, because the function bumps 70 c are superimposed on the function pads 71 c, FIG. 7 shows the function bumps 70 c on the upper level. Similarly, FIG. 7 shows the function electrodes 73 c and 73 f.

ACFs are disposed between the IC 70 and first substrate 71, between the first substrate 71 and between the third substrate 73, and between the second substrate 72 and the third substrate 73, and then applying a pressure on the IC 70 and first substrate 71, the first substrate 71 and the third substrate 73, and the second substrate 72 and the third substrate 73. Between the IC 70 and first substrate 71, the function bumps 70 c and the function pads 71 c should be aligned, and the positioning bumps 70 a and 70 b and the positioning pads 71 a and 71 b should be aligned in a first pressing region. Between the first substrate 71 and the third substrate 73, the function electrodes 71 f and the function electrodes 73 c should be aligned, and the positioning electrodes 71 d and 71 e and the positioning electrodes 73 a and 73 b should be aligned in a second pressing region. Between the second substrate 72 and the third substrate 73, the function electrodes 72 c and the function electrodes 73 f should be aligned, and the positioning electrodes 72 a and 72 b and the positioning electrodes 73 d and 73 e should be aligned in a third pressing region

In the present embodiment, between the first substrate 71 and the third substrate 73, the distance between any two of the function electrodes 71 f is substantially greater than the distance between the positioning electrodes 71 d and 71 e, or the distance between any two of the function electrodes 73 c is substantially greater than the distance between the positioning electrodes 73 a and 73 b. Between the second substrate 72 and the third substrate 73, the distance between any two of the function electrodes 73 c is substantially greater than the distance between the positioning electrodes 73 d and 73 e, or the distance between any two of the function electrodes 72 c is substantially greater than the distance between the positioning electrodes 72 a and 72 b. In the following description, the distance between two function electrodes 71 f is substantially greater than the distance between the positioning electrodes 71 d and 71 e, and the distance between the function electrodes 72 c is substantially greater than the distance between the positioning electrodes 72 a and 72 b.

The positioning electrodes 72 a and 72 b respectively receive signals S72 a and S72 b which have substantially different voltage levels. When the misalignment detection device 7 is applied in a display device. At least one of the signals S72 a and S72 b disregards display device functions. In other words, at least one of the signals S73 a and S73 b is not provided by the display device. For example, the signal S72 a has the same level as a common voltage Vcom of the display device, and the signal S72 b has a ground level GND provided by the misalignment detection device 7 or an external device (not shown).

The detection unit 72 is electrically coupled to and disposed on the second substrate 72. The detection unit 74 detects the signals S72 a and S72 b. When positioning shift occurs in at least one among the first to third pressing regions, the detection unit 74 outputs a fault signal S74. The display device displays incorrect images according to the fault signal S74, and the disposition error can be detected. For example, when the positioning shift occurs between the IC 70 and the first substrate 71 and the misalignment is thus caused between the function bumps 70 c and the function pads 71 c, the positioning bump 70 a is electrically coupled to the positioning pad 71 b or the positioning bump 70 b is electrically coupled to the positioning pad 71 a, at the same time, one function bump 70 c is electrically coupled to a function pad adjacent to the substantially corresponding function pad 71 c. One of the signals S72 a and S72 b is not at the original voltage level. When detecting that the voltage level of one of the signals S72 a and S72 b is changed, the detection unit 74 outputs the fault signal S74 to indicate the positioning shift occurs between the IC 70 and the first substrate 71.

In the present embodiment, the distance between two function pads 71 c of the first substrate 71 is substantially greater than the distance between the positioning pads 71 a and 71 b thereof. When the positioning shift occurs between the IC 70 and the first substrate 71, the positioning bump 70 a has been electrically coupled to the positioning pad 71 b or the positioning bump 70 b has been electrically coupled to the positioning pad 71 a although any one of the function bumps 70 c is not yet electrically coupled to a function pad adjacent to the substantially corresponding function pad 61 c to cause the misalignment. Thus, the positioning shift can be known in advance, decreasing the probability of the misalignment. Similarly, by the greater distance between two function electrodes 71 f substantially greater than the distance between the positioning electrodes 71 d and 71 e and the greater distance between two function electrodes 72 c substantially greater than the distance between the positioning electrodes 72 a and 72 b, the positioning shift in the second region and/or the third pressing region can be known in advance.

In the present embodiment, the distance between two function pads 71 c is substantially greater than the distance between the positioning pads 71 a and 71 b. In some cases, although the positioning shift does not occur between the IC 70 and the first substrate 71, the conductive particles of the ACF form a short path between the positioning bumps 70 a and 70 b and the positioning pads 71 a and 71 b due the shorter distance between the positioning pads 71 a and 71 b. In order to prevent the short path formed by the conductive particles of the ACF, the forms of the positioning pads 71 a and 71 b can be made as shown in FIG. 5. Referring to FIG. 8, the positioning pad 71 a comprising two portions 80 a and 80 b, and the positioning pad 71 a comprising two portions 81 a and 81 b. The distance between the positioning pads 71 a and 71 b has the maximum length Lmax and the minimum length Lmin less than the maximum length Lmax. The distance between two function pads 71 c equal to the maximum length Lmax. The distance between the positioning pads 71 a and 71 b has the maximum length Lmax and the minimum length Lmin. It is assumed that the distance between two function electrodes 71 c is about 20 um, the maximum length Lmax is substantially equal to 20 um, and the minimum length Lmin is substantially less than 20 um. Thus, when the positioning shift occurs between the IC 70 and the first substrate 71 and the misalignment is not yet caused between the function bumps 70 c and the function pads 71 c, the positioning bump 70 a has been electrically coupled to the positioning pad 71 b or the positioning bump 70 b is coupled to the positioning pad 71 a, thereby the positioning shift between the IC 70 and the first substrate 71 can be known in advance. Moreover, because the distance between one portion of the positioning pad 71 a and one portion of the positioning pad 71 b is less than about 20 um, the short path formed by the conductive particles of the ACF can be prevented.

Similarly, the forms of the positioning electrodes 71 d and 71 e of the first substrate 71 and the positioning electrodes 72 a and 72 b of the second substrate 72 can be made as shown in FIG. 5. Referring to FIG. 9, the positioning electrode 71 d comprising two portions 90 a and 90 b, and the positioning electrode 71 e comprising two portions 90 a and 90 b. The distance between the positioning electrodes 71 d and 71 e has the maximum length Lmax and the minimum length Lmin less than the maximum length Lmax. The distance between two function electrodes 71 f equal to the maximum length Lmax. Referring to FIG. 10, the positioning electrode 72 a comprising two portions 100 a and 100 b, and the positioning electrode 72 b comprising two portions 100 a and 100 b. The distance between the positioning electrodes 72 a and 72 b has the maximum length Lmax and the minimum length Lmin less than the maximum length Lmax. The distance between two function electrodes 72 c equal to the maximum length Lmax.

In present embodiment, the positioning bumps 70 a and 70 b are disposed on an outer side of the IC 70, in other words, the positioning bumps 70 a and 70 b are disposed on one of the two sides of the function bumps 70 c, as shown in FIG. 7. On the first substrate 71, the positioning electrodes 71 d and 71 e are disposed on an outer side of the first substrate 71, in other words, the positioning electrodes 71 d and 71 e are disposed on one of the two sides of the function electrodes 71 f. Similarly, on the second substrate 72, the positioning electrodes 72 a and 72 b are disposed on one of the two sides of the function electrodes 72 c. On the third substrate 73, the positioning electrodes 73 a and 73 b are disposed on one of the two sides of the function electrodes 73 c, and the positioning electrodes 73 d and 73 e are disposed on one of the two sides of the function electrodes 73 f.

The display device described above can be a liquid crystal display, an electroluminescent display, a field-emission display, a nano-carbon tube display, or other display. An electroluminescent display has organic (small molecules or macromolecules) or inorganic types. In the above embodiments of the present invention, a liquid crystal display is given as an exemplary display device.

While the present invention has been described by way of example and in terms of the preferred embodiments, it is to be understood that the present invention is not limited to the disclosed embodiments. To the contrary, it is intended to cover various modifications and similar arrangements (as would be apparent to those skilled in the art). Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements. 

What is claimed is:
 1. A misalignment detection device comprising: a first substrate comprising a first positioning pad, a second positioning pad adjacent to the first positioning pad, a first positioning electrode, and a second positioning electrode adjacent to the first positioning electrode; at least one integrated circuit with a first pressing region, disposed on the first substrate, comprising a first positioning bump and a second positioning bump adjacent to the first positioning bump, wherein the first positioning bump and the second positioning bump substantially correspond to the first positioning pad and the second positioning pad in the first pressing region, respectively; a second substrate comprising a third positioning electrode and a fourth positioning electrode adjacent to the third positioning electrode; a third substrate with a second pressing region and a third pressing region, electrically coupled between the first and second substrates, comprising a fifth positioning electrode, a sixth positioning electrode adjacent to the fifth positioning electrode, a seventh positioning electrode, and a eighth positioning electrode adjacent to the seventh positioning electrode, wherein the fifth positioning electrode and the sixth positioning electrode substantially correspond to the first positioning electrode and the second positioning electrode in the second pressing region, respectively, and the seventh positioning electrode and the eighth positioning electrode substantially correspond to the third positioning electrode and the fourth positioning electrode in the third pressing region, respectively; and at least one detection unit electrically coupled to the second substrate, wherein the at least one detection unit outputs a fault signal in response to a positioning shift occurring in at least one of the first, second, and third pressing regions.
 2. The device of claim 1, wherein the third positioning electrode is adapted to receive a first signal, the fourth positioning electrode is adapted to receive a second signal, and the at least one detection unit detects that a level of the first or second signal changes as a result of the positioning shift.
 3. The device of claim 7, wherein the IC comprises a plurality of function bumps, the first substrate comprises a plurality of function pads, and each function pad substantially corresponds to each function bump.
 4. The device of claim 3, wherein a distance between any two of the function pads is substantially greater than a distance between the first positioning pad and the second positioning pad.
 5. The device of claim 3, wherein a distance between any two of the function pads is greater than or equal to the minimum distance between the first positioning pad and the second positioning pad.
 6. The device of claim 3, wherein the maximum distance between the first positioning pad and the second positioning pad is substantially equal to a distance between any two of the function pads.
 7. The device of claim 1, wherein the first substrate comprises a plurality of first function electrodes, and the first function electrodes and the first and second positioning electrodes are disposed on the same side of the first substrate; the second substrate comprises a plurality of second function electrodes, and the second function electrodes and the third and fourth positioning electrodes are disposed on the same side of the second substrate; the third substrate comprises a plurality of third function electrodes, each third function electrode substantially corresponding to each first function electrode, and the third function electrodes and the fifth and sixth positioning electrodes are disposed on a first side of the second substrate; and the third substrate comprises a plurality of fourth function electrodes, each fourth function electrode substantially corresponding to each second function electrode, and the fourth function electrodes and the seventh and eighth positioning electrodes are disposed on a second side of the second substrate.
 8. The device of claim 7, wherein a distance between any two of the first function electrodes is substantially greater than a distance between the first positioning electrode and the second positioning electrode.
 9. The device of claim 7, wherein a distance between any two of the third function electrodes is substantially greater than a distance between the fifth positioning electrode and the sixth positioning electrode.
 10. The device of claim 7, wherein a distance between any two of the second function electrodes is substantially greater than a distance between the third positioning electrode and the fourth positioning electrode.
 11. The device of claim 7, wherein a distance between any two of the fourth function electrodes is substantially greater than a distance between the seventh positioning electrode and the eighth positioning electrode.
 12. The device of claim 7, wherein the first and second positioning electrodes are disposed on an outer side of the first substrate.
 13. The device of claim 7, wherein the third and fourth positioning electrodes are disposed on an outer side of the second substrate.
 14. The device of claim 7, wherein the fifth and sixth positioning electrodes are disposed on an outer side of the third substrate.
 15. The device of claim 7, wherein the seventh and eighth positioning electrodes are disposed on an outer side of the third substrate.
 16. The device of claim 1, wherein the first and second positioning bumps are disposed on an outer side of the IC.
 17. The device of claim 1, wherein the first positioning pad comprises a first portion and a second portion whose area is smaller than the area of the first portion, and the second positioning pad comprises a third portion and a fourth portion whose area is smaller than the third portion; and wherein the second portion and the fourth portion are disposed between the first portion and the third portion 